Abrasive strip holding and tightening mechanism



Feb. 15, 1966 J. F. VOSBURG 3,234,694

ABRASIVE STRIP HOLDING AND TIGHTENING MECHANISM Filed Nov. 6, 1963 INVENTOR. JOHN F VO B R T OIQNEYS United States Patent Ofiice 3,234,694 Patented Feb. 15, 1966 3,234,694 ABRASIVE STRIP HOLDING AND TIGHTENING MECHANISM John F. Vosburg, 340 Broad St., Salamanca, N.Y. Filed Nov. 6, 1963, Ser. No. 321,828 8 Claims. (Cl. 51368) This invention relates to a mechanism for holding and tightening a removable abrasive sheet or strip in place about the periphery of a wheel.

It is an object of this invention to provide a quick acting, dependable and durable mechanism for holding and retaining an abrasive strip in position on a sanding wheel, and for tightening an abrasive strip about a wheel or the like.

Another object of this invention is to provide a holding and tightening mechanism which facilitates changing of abrasive sheets.

A further object of this invention is to provide a holding and tightening mechanism which can accommodate sheets of various abrasive grades.

Still another object of this invention is to provide a holding and tightening mechanism which can accommodate abrasive strips of various widths.

In a presently contemplated, illustrative embodiment thereof, an abrasive strip holding and tightening mechanism of my invention utilizes a pair of rollers carried by a sanding wheel to grip and apply tension to the ends of an abrasive strip. The ends of the strip are passed between the rollers, which are then moved into gripping relation by a quick acting, over center toggle mechanism acting on one of the rollers to lock the strip ends therebetween. The strip is tightened about the wheel by rotating one of the rollers while the gripping relationship therebetween is maintained, in a direction drawing the strip ends further between the rollers. Unlocking of the toggle mechanism separates the rollers, releasing the strip for easy removal and replacement.

These and other objects, advantages and characterizing features of my invention will become more apparent upon consideration of the following detailed description of an illustrative embodiment thereof, in conjunction with the accompanying drawing depicting the same, in which:

FIG. 1 is a fragmentary sectional view of a sanding wheel provided with a holding and tightening mechanism of my invention, taken about on line 11 of FIG. 2;

FIG. 2 is a sectional view thereof, on a reduced scale, taken along line 2-2 of FIG. 1; and

FIG. 3 is a sectional view thereof taken along line 3-3 of FIG. 1.

Referring to the drawings, FIG. 1 shows an abrasive strip holding and tightening mechanism of my invention, generally designated 10, mounted on a sanding wheel 12. Wheel 12 includes a central hub 14 adapted for attachment to any suitable drive shaft means (not shown), a web portion 16 carried by the hub, and a flanged outer peripheral rim section 18. The flanged peripheral section 18 is provided with a transverse slot 20 (FIGS. 2 and 3) which extends radially inwardly into web portion 16. S-lot 20 is adapted to receive the ends 17 of an abrasive strip 15 which can be of any type desired. Web 16 also has an opening 22 formed therein, of generally ellipsoidal shape as indicated in phantom in FIG. 1, in communication with slot 20 for purposes explained hereinbelow.

Tightening mechanism includes a pair of support brackets 24, 25 attached to the underside of flanged periphery 18 and extending radially inwardly thereof on opposite sides of web 16. Brackets 24, 25 each have a slot 26 formed therein in axial alignment with slot 20, for receiving the ends of abrasive strip 15.

Journaled to support brackets 24, 25 and extending through web opening 22 are fixed and slidable roller members 27 and 28, respectively. Fixed roller 27 has a series of longitudinally extending splines 30 formed on its periphery to provide a toothed sheet engaging surface coacting with movable roller 28 to eflectively grip and clamp the brasive sheet ends 17 therebetween. The axle of fixed roller 27 has an end 32 extending outwardly from bracket 24 and formed to receive any suitable wrench or similar tool (not shown) for rotation of the fixed roller 27. Rotation of roller 27 normally is limited, however, to a counterclockwise direction, as viewed in FIG. 1, by the latching action of a weighted, one-way pawl 34 pivotally attached to bracket 25 and gravity urged, against a stop, to its spline engaging position shown in FIG. 1.

Movable roller 28 is formed with a jacket 36 of a suitable resiliently yieldable material providing a friction surface, such as rubber. Jacket 36 is bonded to a core 38, and provides a resiliently yieldable bearing and backup surface for the relatively unyieldable splines 30 of gear roller 27 The axle 40 of roller 28 rides in a trackway formed by generally parallel guide slots 42 in brackets 24 and 25 and extending in a direction normal to slots 26. This trackway provides for lateral movement of roller 28 in opening 22, towards and away from fixed roller 27, and opening 22 permits rollers 27, 28 to project into slot 20.

To impart movement to roller 28, there is provided a quick acting, over center toggle mechanism, generally designated 44, on each side of the wheel web 16. Each toggle 44 includes a lever arm 46 pivoted between its ends at 47 on the associated bracket 24, 25, and a link 48 pivotally connected at its ends to roller axle 40 and to lever arm 46. counterclockwise rotation of either lever arm 46, as viewed in FIG. 1, slides axle 40 along trackway 42 in a direction retracting roller 28 from the gripping position of FIG. 1. Clockwise rotation of either lever arm, as viewed in FIG. 1, causes axle 40 to slide along trackway 42 in a direction driving roller 28 toward gear roller 26. Toggles 44 are held in the clamping position of FIG. 1 by overcenter action, as clearly shown in FIG. 1, while excessive overcenter rotation of lever arms 46 in a roller closing direction is prevented by stop pins 50 fixed to support brackets 24, 25. The resilient yielding of roller jacket 36 accommodates the overcenter action of toggles 44.

In operation, one of the toggles 44 is actuated to move roller 28 away from roller 27. An abrasive strip 15 is placed about the periphery 18 of wheel 12, and strip ends 17 are inserted into slots 20 and 26, between the separated rollers. With the strip ends in this position, one of the toggles 44 is actuated to shift roller 28 toward gear roller 27, clamping the strip ends 17 therebetween. Continued rotation of lever arms 46, past the dead center position of the toggles, brings them against the stops 50, effectively locking roller 28 in clamping position securing the strip ends 17 between rollers 27 and 28. The resiliently yieldable jacket 36 of roller 28 accommodates such overcenter movement while reacting to hold roller 28 locked in clamping position.

To tighten the abrasive strip about the wheel, gear roller 27 is rotated, counterclockwise as viewed in FIG. 1, by any suitable wrench or like tool applied to the axle end 32 of gear roller 27. This also rotates roller 28, clockwise as viewed in FIG. 1, drawing the belt ends 17 further inwardly between the rollers, tightening the belt while continuing to clamp it and hold it in place.

Whenever it is desired to remove the belt, lever arms 46 are rotated counterclockwise as viewed in FIG. 1, by actuating either of them, separating roller 28 from roller 27 and thereby freeing the belt ends.

Thus itwill be appreciatedthat this inventionprovides an eflicient means of retaining an abrasive belt about the periphery of a wheel. Splines 30 press the strip ends 17 against the resilient surface 36 of roller 28, providing a positive gripping action. Slipping of roller 27, and subsequent loosening of the abrasive strip, is prevented by pawl 50, which however, can be release-d should it be desirer to rotate roller 27 in the opposite direction. Any variation in the thicknesses of belts used is compensated for by deformation of the resilient jacket 36, which is adapted to contact roller 27, or substantially so, in the absence of strip ends therebetween. The resilient jacket 36 also compensates for any wearor looseness which may develop. The over center toggle mechanism allows quick opening and closing of the roller members to facilitate release and clamping of the strip. The strip is securely held at all times but can be tightened at any time Without unlocking the mechanism.

The toggle mechanism can be actuated from either side of the wheel for greater convenience. At the same time, (the entire holding and tightening mechanism is confined within the outline of the wheel. The abrasive strip can extend the full width of the wheel. Abrasive strips of different widths can be accommodated, with longer rollers being provided if necessary.

It is to be understood that the foregoing detailed description is given by way of illustration only, and that various modifications and variations of the strip tightening mechanism described in detail herein can be made without departing from the spirit and'scope of the invention.

Having fully disclosed and completely described my invention, together with its mode of operation, what I claim as new is:

1. An abrasive strip holding and tightening mechanism comprising:

'(a) a wheel having aflanged outer periphery for receiving thereon an abrasive strip;

(b) a pair of bracket members attached to said flanged periphery having a generally radial slot formed therein for receiving the ends of an abrasive strip;

(c) a pair of roller members journaled on said brackets and disposed to retain such strip ends therebetween;

.(d) a toggle mechanism operatively connected to one of said roller members for moving the same into and out of strip end clamping relation to'the other of said roller members; andv (e) latch means engaging one of said roller members to limit the direction of rotation thereof.

2. A mechanism as set forthin claim 1, in which said one roller has a resiliently yieldable. outer surface and the other roller member has a relatively unyielding gripping surface.

3. A device as set forth in claim 2 in which:

(a) said gripping surface is splined; and

(b) said latch means includes a pawl mounted on one of said brackets for engaging said splines.

4. A device as set forth in claim 2 in which said other roller member has an axial extension adapted to receive a tool for rotation of said other roller member.

5. A mechanism as set forth in claim 1 in which:

(a) -said bracket :members have a trackway formed therein normal'to said slotgand (b) said one roller member has axial extensions slidably disposed in said trackway, said toggle mechanism providing lateral motion of said one roller.

6. A device as set fort 'hin claim 5 in which:

(a) said toggle mechanism includes a lever arm mounted on each of said bracket members, and link members extending between and pivotally connected to said lever arms and said .one roller member respectively; and

(b) astop fixedto each of said bracket members to prevent excessive overcenter movement of said lever arms.

7. In a wheel adapted to carry an abrasive strip, a mechanism for holding and tightening an abrasive strip about said wheel comprising:

(a) support brackets carried by said wheel, said brackets providing a trackway;

(b) a resilient roller-slidably disposed in said trackway;

(c) a toothed roller journaled on said support brackets adjacent'said resilient roller;

(d) means conveyingthe ends of an abrasive strip between-said rollers;

(e) an overcenter toggle mechanism pivoted to one of said support brackets and 'operatively connected to said resilient roller, said mechanism acting to retain saidresilient roller in abutting relationship with said toothed roller 'to 'lock such strip ends therebetween;

( f) said toothed roller being disposed for rotation against said resilient roller to draw such strip ends further therebetween; and

(g) a pawl attached to one'of said support brackets in engagement with said toothed roller to prevent release of tension on such strip other than by releasing said resilient roller through said mechanism.

8. The combination set forth in claim 7 in which said means includes a radially inwardlyextending slot formed in'said wheel, said rollers being disposed on opposite sides of said slot in communication therewith.

.References Cited by the Examiner UNITED STATES PATENTS 1,302,724 5/1919 Solem 51-368 2,344,550 3/1944 Knowlton 5l-368 ROBERT C. RIORDON, Primary Examiner.

LESTERN M. SWINGLE, Examiner. 

1. AN ABRASIVE STRIP HOLDING AND TIGHTENING MECHANISM COMPRISING: (A) A WHEEL HAVING A FLANGED OUTER PERIPHERY FOR RECEIVING THEREON AN ABRASIVE STRIP; (B) A PAIR OF BRACKET MEMBERS ATTACHED TO SAID FLANGED PERIPHERY HAVING A GENERALLY RADIAL SLOT FORMED THEREIN FOR RECEIVING THE ENDS OF AN ABRASIVE STRIP; (C) A PAIR OF ROLLER MEMBERS JOURNALED ON SAID BRACKETS AND DISPOSED TO RETAIN SUCH STRIP ENDS THEREBETWEEN; (D) A TOGGLE MECHANISM OPERATIVELY CONNECTED TO ONE OF SAID ROLLER MEMBERS FOR MOVING THE SAME INTO AND OUT OF STRIP END CLAMPING RELATION TO THE OTHER OF SAID ROLLER MEMBERS; AND (E) LATCH MEANS ENGAGING ONE OF SAID ROLLER MEMBERS TO LIMIT THE DIRECTION OF ROTATION THEREOF. 